As you dont want to show Sub-seg(DIM2), go to presentation tab and choose the Hide Column and for the next two expressions in Presentation tab select respecpective expressions and write in Column Label

in design tab, there is a check box 'Always Show Design Menu Items'Make it selected.press ok.

Now go to your pivot table, right click on it u will see the option 'Custom Format Cell' click it.Now small window will appear. select >=50000 or select expression header you have and click on Bold check box.Press Ok